Wedge coupled joint



Sept 22, i931- E. M. ERLANDsoN 1,823,9'3'1 WEDGE COUPLED JOINT Filed NOV. 14, 1930 Inventar; Eff/Z M E'rZazzdJazz,

Patented Sept. 22, 1931 :EMIL M. EnLA'rInscrI, or Los ANGELES, CALIFORNIA kwenen yocurren Jorim Application filed November 14, 1930. Serial No. 495,659.:`

ln this specification and the accompanying drawings, 'l shall describe and show a preferred form of my invention, and specifically mention certain of its more important o b jects. l do not limit myself to the forms disclosed, since various changes and adaptations may be made therein without departing from the essence of my invention as hereinafter claimed; and objects and advantages, other l@ than those specifically mentioned, are included within its scope. A My invention relates to improvements in couplings, and particularly to means for making wedge-coupledl joints between lonl gitudinally abutted members, such as drilling bit cutters and their' body members.

first, to provide improved means for coupling longitudinally abutted members in such a manner as to maintain their abutting faces in compression at all times, Without resorting to the use of screw-threads for accomplishing such compression; second, to furnish y improved facilities for drawing the abutting faces of longitudinally positioned members into very close contact under compression by means of force applied by hammer blows; third, to secure improved means for tightenino` wedges in so-called wedgeand pinv joints, and for thereafter maintaining them in their tightened position; and, fourth, toaccoin` plish the above objects, and others that will appear below, by means of simple and relatively inexpensive construction.`

My objects are attained in the manner idllustrated in the accompanying drawings, in which i Figure 1 is an elevation of two longitudinally abutted members,-coupled together by my improved means; Y

Figure 2 is a. partial sectional elevation of the above construction, taken on the line 2-2 of 1Eig. 1; Y

vlifigure 3 is an elevation of two longitudinally abutted members, coupled together by means of a different specific type of my invention; n j

Figure 4 is a partial sectional elevation of the construction shown in Fig. 3, the section Among ,4. u; trie principal objects of the invention are,

being takenon the line e-lof the last said figure; n

' Figure 5 is anY isometric view of the special form of screw plug that I employ for positioning and locking the wedge; i

' Figure v6 is a front 'elevation of a preferred form of spring-wire clip that l employ in cooperation with the plug shown in lEig. 5 and,

Figure i' is a perspective Aview of the wrench that l employ for tightening up the parts'lof my improved oint. y j

Similar reference numerals refer to similar parts throughoutthe several views.

lillyvinvention is particularly applicable to such uses as. the positioning of end-cutting elements upon earth drilling bit bodies, and I have selected this application forthe purpose of illustrating and describing it. ln the drawings l have' shown a pair of longitudinally abutted, joined members 11 and 1a. Y Of these, the member 11 may be considered for exampleas being the body of an earth drilling bit, and the member 12 as the upper end of a removable cutting element thereof.

ln any form of my invention, one of the joined elements isprovided with an axially extendingk pin V13. rlhe other cooperating member is provided with an axial bore 14, into which said axial pin may beV inserted snuglv. rlfhe abutting faces of the pairs of `members are accurately turned perpendicu` larly to the axis `of pin 13, so as to adapt `them to seat upon each other, yas indicated at 15 in Figs. 1 and 3.

' Pin 13 isprovidedwith' a longitudinal slot therethrough, th'esurface of the other end of the slot being perpendicular .to the axis, as indicated at 16, and the surface of the inner end of the slot being sloped with respect to the axis, as indicated at 17. Correspondingslots are formed through body members 11, adapted vto cooperate with the slots through the pins, to enable a wedge 18 to be inserted therethrough, and be driven home for tightening up the joint between the abutting members. vThus the slots in the body members. areentirely similar to the slots in the pins, but the f former slots are longitudinally displaced with respect to the latter slots, to enable wedges 18 to perform their intended functions.' vSlot 'plugitself is positively prevented from be-Y surfaces 19 vand20 in the drawings are above slot surface 1G of the pin; and slot surface 17 of the pin is below slot surfaces 21 and 22 of the body members. Thus, in the dra-wings, when wedges 18 are Vdriven home, the cutting elements will be pulled tightly upwardly against the corresponding body members, so as to elfect a very tight joint at 15,.

lt usually is desirable to provide some form or radial key on one of the pair of abutting members, such as keys 23on cutting elements `12. These keys, of course, are adapted to snugly lit the sides of a radial slot 2a in the cooperating member of the abutting pair.

The above described construction provides a well known and perfectly satisfactory joint for longitudinally abutted members, so long as the wedges 18 are kept tightly driven home. Torsional stresses yare prevented from being imposed upon the wedges by means of keys 28 and their cooperating slots 24, and the 'construction thus prevents any angular or longitudinal displacement between the cooperating abutting members. Y f

A ln certain uses, such as in earth drilling, where shocks and vibrations due to operation are very great, it has been found to be very diflicult or practically impossible to keep wedges 18 tightly driven home, unless special means are provided for this purpose. lt is with these special means that the Ypresent invention has to do. I have devised a method whereby the wedges may be very tightly driven home in the first instance, and then be prevented from becoming loose in operation. Such devices as simple'set-screws, follow-up plugs screwed against the outer ends of the wedges, and similar devices, are inadequate. They invariably work loose in time, and thus fail to perform their functions.

Passing to a detailed description of my invention, I have found that a follow-up plug over the outer end of the wedge is effective to maintain a tight joint between longitudinally abutted wedge-coupled members, only if the comingunscrewed, and only if the wedge tightening means are independent of the plug tightening means. That is to say,.it appears to be impossible to secure and maintain a pei` fectly tight oint of this kind, if only the plug itself is depended upon for tightening the wedges. To secure the best possible results, it appears to be lnecessary to have the plug tightening means cooperate with the wedge tightening means, but ,the lattershould in a measure be 'independent of the former. The two elements should be tightened concurrently, but not one by means of the other.

,InV my joint I provide a special forni of follow-up plug 25, over the head of wet ge 18. This plug is adapted to be `screwed tightly against the head ofthe wedge by means of screw threads 26 in a tapped hole in the body member, through which hole the wedge yis inserted. This plug has crossslots 27 therethrough, at right angles to each other. The edges 28, formed by the intersection ofthese cross slots, are intermediately intercepted by means of a circular groove 29 turned or milled in the body of the plug. The plug may be directly inserted in a hole tapped within the body member,- as shown in F ig. l, or it may be inserted in a tapped bushing 8O that is inserted within a vbore inthe body of the hold- Aer, and welded therein as by the circular weld 31, shown in Figs. 1 and 2. The latter construction is often preferable in severe service, since it permits of burning out the bushing, and of replacing it with a new one,

with aV minimum of time and expense.

Tn any form of my invention, he wedge 18 is first driven home as tightly as po, ble.

Plug 25 is then inserted, and tightened up against the head of the wedge by means of a siecial wrench, such as is indicated in Fig. 7. The working portion of this wrench is of a cross-section that adapts it to be inserted through either one of the cross-slots 2'?. Its `working end 32 is thus adapted to Contact with the head of wedge 18, and the wedge may be further Vdriven home by using the wrench as a dolly bar and applying hammer blows upon its outer end To effect the greatest possible insertion of wedge V18, the method is to first drive the wedge lionie by means of hammer blows upon its head, then plug 2T is inserted and screwed home againstthe end of the wedge bymeaiis of the wrench. Finally additional .hammer blows are applied to end of the wrench while a strong torsional force is being maintained upon it by means of its handle 34. In' this way the plug mav be tightened to the utmost extent, and at the same time that the wedge is being driven home. The plug will thus be made to not only follow-up all movements 0f the wedge,

but will 'be made to actually follow-up the compression of the material of the wedge that is caused by the hammer blows.

./Vhen the wedge has been tightened, and

plug 25 has been screwed home thereagainst in the manner described, it still is necessary to insure the plug against any unscrewing.

There are several means of accomplishing this, of which two are illustrated. One method indicated 4in Figs. 1 and 2 is to tap a hole into the outer end of wedge 18, tight'- Tn this way,

severe services,'such as is required ofL earth drilling tools. l therefore employ a iillister-headedscrew having deep cross-slots 36 in its head. l then snap into place the clip shown in Fig. 6, within circular groove 29 of the plug, and within one of the cross slots 01"' the illister-headed screw. This clip is made ci spring wire centrally doubled back on itselrn to form a hey-head 37, adapted for being inserted within one of the slots of the lillister-headed screw. The legs 38 of the clip are so shaped as toadapt them to be sprung into circular grooveQS). Allof this construction is indicatedl in Figs. l and 2. rihe spring clip prevents screw 35 from backing out, and therefore prevents plug 25 :troni becoming unscrewed.

An alternative form of locking the plug 25 is illustrated in Figs. 3 `and 4. Although it has .eeen found that a screw 35, when inserted inr the head of the wedge, will inevitably become loosened by shocks and vibrations under adverse service conditions, this does not appear to be the case of a screw 39 that is inserted directly into the body member into which the wedge is driven. Therefore it is possible to provide a washer l0 raving a tongue 41 laterally extending therefrom, the tongue being given the fshape indicatedin Fig. e, and this washer being held in place by means of screw 39. rEhe end ot tongue 4l is of a width that closely corresponds to the width of cress-A slots 27 and is bentvinto'one of these slots 'asfindicated'in F ig.

@ther means fer eiiiectually preventing plug 25 from becoming unscrewed in service will occur to those familiar with the art involved, and such means are contemplated by me.

l claim as my invention l. device of the character described,

comprising; abutting -members joined by means of a wedge inserted'through a tapped hole in one or" said members; and a plug screwed into said hole against the head of said wedge; said plug having an opening therethrough into which a tool may be inn serted and whereby the wedge may be further driven and the plug be simultaneously tightened.

9.. A device of the character described, i

comprising; abutting members joined by means of a wedge inserted through a tapped hole in one of said members; and a plug screwed into said hole against the head of saidwedge; said plug beingperforate and thus afording means for engagement Vby a tool that is adapted for simultaneously tightening the plug while acting as a dolly-bar forturther driving of the wedge.

3. A device of the character described, comprising; abutting members joined by means of awedge inserted through a tapped hole in one ot' said members; and a plug screwed into said hole against the head of said wedge; lsaid plug having cross-slots therethrough wherein a bar may be inserted for'tightening the plug and for simultaneously acting as a dolly-bar for further driving of the wedge.

4. A device of thev character described, comprising; abutting members joined by means of a wedge inserted through a'tappedV hole in one of said members; and a plug screwed into said hole against the head of saidwedge; said plug being perforate and adapted thereby for permitting a tool to passtherethrough for Jfurther driving of the wedge, wherein said tapped hole is formed in a bushing, and wherein the bushing' is inserted in a correspondingly dimensioned .hole in one fof said joined members and screwing of said plug is prevented.

7. The construction set forth in claim 3 in cmobination with a screw tapped into the head of said wedge and extendino` into one of said slots, whereby the unintentional unscrewing of said plug is prevented; and

- means carried by said plug for preventing the unintentional unscrewing of said screw.

8. The construction set forth in claim 3 in combination with means carried by one of said joined members and engaging ay wall of one of said slots and adapted thereby to prevent the unintentional unscrewing of said plug.

EMIL ERLANDSON. 

